[en] A modelling analysis of the transportation system is described, focused on the market penetration of different transportation technologies (including Learning-by-Doing) until the year 2050. A general outline of the work and first preliminary results are presented. (author)

[en] In a field study in Zuerich, aerosol number size distributions and mass concentrations were measured simultaneously on a kerbside (main road with traffic lights) and a background monitoring station. From the concentration differences real-life emission factors were derived using NO_x concentrations to calculate dilution factors. (author)

[en] Tropospheric NO₂ vertical columns derived from the GOME (Global Ozone Monitoring Experiment) instrument, deployed on the ERS-2 satellite, were compared with ground measurements of NO₂ in the Lombardy region. Under cloud free conditions, the in-situ measurements were reasonably correlated with the tropospheric NO₂ columns obtained from GOME. This analysis will contribute to the validation of tropospheric data obtained by measurements from space. (author)

[en] To study the allocation of recently fixed carbon (photo assimilates) in mature deciduous trees, we apply pulse labelling experiments by enclosing small branches in branch bags with highly ¹³C enriched CO₂ (author)

[en] Within the EU project CARBOMONT two differently managed grassland study sites are investigated at Seebodenalp (Central Switzerland). To characterize the CO₂ flux dynamics the net ecosystem exchange rate of CO₂ (NEE) is partitioned into the main carbon fluxes net photosynthetic assimilation and ecosystem respiration using stable C isotopes. First results show that the exceptionally dry summer 2003 affected the fluxes in particular on the extensively managed area. (author)

[en] Efflux of CO₂ and water vapor from soils influence the isotopic composition of above ground air. Prolonged hot and dry weather conditions can cause significant changes in soil air and soil water ¹³C and ¹⁸O isotope ratios. After a period of hot and dry weather in summer 2003 soil samples showed an increase of up to 0.5% on(delta)¹⁸O of soil water in all sampled depths (0-12cm), and at the same time (delta)¹³C of soil air CO₂ rose by 0.4% with an up to four-fold decrease of soil CO₂ concentration. These effects are thought to be caused by alteration of the soil structure and changes in microbial activity due to dryness. (author)

[en] Research at PSI comprises all aspects of human energy use, with the ultimate goal of promoting development towards a sustainable energy supply system. In the General Energy Research Department, technologies are being advanced for the utilization of renewable energy sources, low-loss energy storage, efficient conversion, and low emission energy use. Experimental and model-based assessment of these emissions forms the basis of a comprehensive assessment of economic, ecological and environmental consequences, for both present and future energy supply systems. The research program of the department is centered around 1) development, use, and characterisation of catalysts for energy technologies in many different fields, like e.g. the partial oxidation of methanol for hydrogen production, the processing of methane by catalytic combustion and reforming; 2) use of concentrated solar radiation to induce chemical conversions, thereby producing energy carriers; 3) development of efficient, less polluting combustion engines and burners by advancing the detailed understanding of reaction mechanisms and combustion pathways; 4) research and development of low temperature polymer electrolyte fuel cells, novel batteries and capacitors, with applications envisaged for electric vehicles, photovoltaics and on-site load leveling; 5) experimental and model based research concerning transportation and chemistry of atmospheric trace gases related to anthropogenic energy transformations. Progress in 2000 in these topical areas is described in this report. A list of scientific publications in 2002 is also provided

[en] CO₂ fluxes were measured by the eddy covariance method from the mid of spring until the first snow fall (17 May to 25 September 2002) above a drained wet land in the Swiss central Alps. The impact of agricultural management on the CO₂ budget is quantified on fields used as pasture or meadow. Cattle grazing and grass cut reduced the CO₂ uptake significantly. (author)